Extended description

When you run this command on a worker, that worker leaves the swarm.

You can use the --force option on a manager to remove it from the swarm.
However, this does not reconfigure the swarm to ensure that there are enough
managers to maintain a quorum in the swarm. The safe way to remove a manager
from a swarm is to demote it to a worker and then direct it to leave the quorum
without using --force. Only use --force in situations where the swarm will
no longer be used after the manager leaves, such as in a single-node swarm.

The node will still appear in the node list, and marked as down. It no longer
affects swarm operation, but a long list of down nodes can clutter the node
list. To remove an inactive node from the list, use the node rm
command.